| 
Stephanie Valberg
Veterinary Population Medicine |
|
Jim Mickelson
Veterinary Biosciences
|
|
Many young
foals die each year despite advances in neonatal intensive care
and the best veterinary treatment available. These deaths are devastating
for the animals' owners. However, the work of Stephanie Valberg
and Jim Mickelson in the College of Veterinary Medicine has enabled
future prevention of the disease.
Valberg and Mickelson identified an inherited disorder called glycogen
branching enzyme deficiency (GBED) in American quarter horses and
related breeds. This disease appears to be the cause for many unexplained
stillbirths and deaths of young foals.
Affected foals are often born dead, weak at birth with a low body
temperature, dead by eight weeks of age due to cardiac arrest, or
euthanized because they become weak and are unable to rise. GBED
foal tissues show no normal sugar (glycogen) when viewed under a
microscope, while they display excessive amounts of an abnormal
sugar (polysaccharide). How do horses get the disease? Genetic analysis
indicates the disease is an autosomal recessive trait, which means
both the stallion and mare must carry and pass on the mutant gene
for it to affect the foal.
What does this research mean?
Ph.D. student Tara Ward, working in Mickelson's laboratory, identified
the chromosomal location and specific mutation in the mutant horse
GBE1 gene that causes this devastating disease. GBED is the equine
equivalent of a rare condition in humans known as glycogen storage
disease type IV.
This exciting discovery is another demonstration of the ability
of state-of-the-art comparative medicine and molecular genetic approaches
to unravel the basic causes of disease in domestic animal species.
Work is now ongoing to determine the prevalence of GBED in the United
States quarter horse population and to estimate its overall role
in foal death and late-term abortion. A test is offered for horse
breeders to determine whether mares and stallions are carriers,
thereby enabling the breeders to reduce or eliminate production
of GBED foals.
For more information, go to: www.academic-server.cvm.umn.edu/neuromuscularlab/immune.htm |
